Just had a clone jet get badly enlarged after 4-5 uses (probably 10 hours or so in total). It may have had something with wrapping some aluminum foil around the pricker rod (maybe it was too tight in the "strangled" part of the upper generator and forced the needle against the jet, but still it's an incredibly short usefulness of a brand new jet. The needle didn't had any fishhook end (checked with a 10x magnifying glass before installing it). So now the question is: are original Petromax jets much more durable? How long can these be expected to last in normal use?